SOLVED Mach 1/Mahayana Dual Pedal Switch Pop

[The Grand Wazoo]

Greetings,

Well there is no shortage of switch pop posts. I'm at my wits end here. I've read more than I care to about switch pop. Unfortunately, none have solved my issue. If anyone has ideas of what the issue can be, I would welcome your input.

• On the Mach 1 side, I get a pop when engaging and disengaging.
• On the Mahayana side, I get a pop when engaging but not disengaging.
• On the 4PDT order switch I get a pop both ways.
• Changing the order switch does not change the behavior of the Mach 1 or Mahayana popping.

Here's what I've tried.

• Went through the @comradehoser troubleshooting order of operation
  • Verified component values
  • Voltage reading for ICs and transistors (below)
  • Continuity checks between components and off-board items
  • DIdn't use the audio probe because I'm getting the effect - they sound great! - they just pop
• Tried putting a 1M pull down resistor on the output jack - no help
• 1M resistors from the 3PDT switch ground to output - no help
• Disconnected all LEDs - no help
• Put a 100nF cap across the input terminals on the 3PDT switch
• 
  • This actually helped a great deal but rolled off ALL of the high end.

Probing and measurements are in the attachments.

EDIT: I tried star grounding and brought all grounds to the DC breakout board. That didn't help. Then I removed the order switch and hooked things up as if it was a simple dual pedal, Mach 1 going into the Mahayana. No help. Then I disconnected the Mahayana altogether so that only the Mach 1 was operating. No help. Not sure what to check next to get rid of the popping.

 

[The Grand Wazoo]

Anyone? Anyone? Bueller? Bueller?

 

[Bret608]

I had a bad pop issue on BB-type build last spring. It ended up needing a smaller pull down resistor at the output (100k or rather than 1m) and a small resistor (2.2k worked for me) in series with the output. Do either of these have something in that role?

 

[The Grand Wazoo]

I had a bad pop issue on BB-type build last spring. It ended up needing a smaller pull down resistor at the output (100k or rather than 1m) and a small resistor (2.2k worked for me) in series with the output. Do either of these have something in that role?

Sort of. The volume pot is the last thing in the circuit for both. A100K for Mach 1 and B100K for Mahayana.

 

[The Grand Wazoo]

I'm still running with just the Mach 1 connected in the enclosure. So it's as if it is a single pedal.

Here is what I've done that has been effective. I had initially put a 1M resistor from the output to ground. But I had done this on the jack. Now I've placed a 1M resistor from the board output to ground. So, the board output now has 2 wires in it. One going to the 3PDT breakout board and the other to one side of a 1M resistor. The other side of that 1M resistor is going ground.

Is there any reason that this wouldn't work on the Mahayana board as well? What about re-introducing the order switch? Is this messing up the output impedance of the circuits?

I appreciate the community's input. Thanks!

 

[The Grand Wazoo]

So this fix is finicky. I still get a very slight pop it I the acceptable range. You have to max the co,use and gain to really make it pop. What is odd is the very specific wiring it wanted.

EDIT:

1. Tried wiring output lug of 3PDT switch -> 1M resistor -> ground lug of 3PDT switch. No dice. Still popping.
2. Tried wiring onboard output pad -> 1M resistor -> 3PDT ground lug. No dice. Still popping.
3. Finally, wired board output pad -> 1M resistor -> ground lug of output jack. THIS is what worked. Does that strike anyone here as oddly specific?

I still have to wire the Mahayana circuit and the order switch back in. I’m planning on wiring the Mahayana the same way. Is there any treatment to the order switch that I should consider?